This is a new, unopened item. I am selling it because I haven't had the opportunity to use it. It's the perfect size for a 500ml plastic bottle. Made with the same Clarino material as school backpacks, the exterior is waterproof. The interior is nylon-lined. It attaches with sturdy hook-and-loop fasteners. It's durable enough for daily use. Material: Clarino Size: Approximately 9.0cm wide x 22.5cm high Retail Price: 3600 yen This is the Ikeda-ya school backpack's optional multi-functional pocket, a cylindrical pocket that attaches to the side belt of the backpack. It's convenient for storing items like recorders or folding umbrellas, which can take up space in the backpack and make it difficult to fit other things.